Export android.content.flags.enable_update_service_bindings.

Allow enable_update_service_bindings to be exported so that applications
may start utilizing it.

NO_EXPORTED_FLAG_ADDITION_CHECK=EXIST_IN_API flag:android.content.flags.enable_update_service_bindings

Bug: 424003130
Flag: android.content.flags.enable_update_service_bindings
Test: atest android.app.cts.service.ServiceTest
Change-Id: I0e4a210fb2bde9cb81c72bc8945d66aa066d0ae5